链霉菌HP-S-01降解高效氯氰菊酯的特性及其动力学

研究不同接菌量、温度、pH、装液量和农药初始浓度对链霉菌HP-S-01降解高效氯氰菊酯的影响。结果表明,在接菌量为0.6 g/L、28°C、pH 7.5和装液量为50 mL/250 mL三角瓶条件下培养3 d,该链霉菌对100 mg/L高效氯氰菊酯降解率达到96%以上。链霉菌HP-S-01还能明显降解高效氟氯氰菊酯、高效氯氟氰菊酯、右旋苯醚菊酯和胺菊酯等拟除虫菊酯农药,且降解过程符合一级动力学模型,降解半衰期分别为0.78、0.88、1.08和1.24 d。采用Andrews方程对链霉菌HP-S-01降解高效氯氰菊酯的过程进行拟合,其动力学参数为qmax=1.826 3 d?1,Ks=58.951 3 mg/L,Ki=359.378 2 mg/L,该链霉菌降解高效氯氰菊酯最佳的初始浓度为145.553 5 mg/L,试验数据与该动力学方程拟合较好。     

高效氯氰菊酯降解菌JCN13的分离鉴定及降解特性研究

从生产高效氯氰菊酯的农药厂污水曝气池中,分离到一株能降解高效氯氰菊酯并以之为唯一碳源进行生长的细菌JCN13.经生理生化试验和16S rDNA分析,鉴定菌株JCN13为沙雷菌属(Serratia sp.).气相色谱检测,菌株JCN13在4 d内对100 mg/L高效氯氰菊酯的降解率为89%,8 d内基本降解完全.经气质联用检测,发现高效氯氰菊酯在被菌株JCN13降解的过程中存在异构体的转化.     

EFFECTIVENESS OF BETA-CYPERMETHRIN ON GLUTAMIC- PYRUVIC TRANSAMINASE (GPT) AND GLUTAMIC-OXALOACETIC TRANSAMINASE (GOT) ACTIVITIES FROM CRUCIAN CARP (CARASSIUS AURATUS) SERUM

Synthetic pyrethroids are considered as possible sub-stitutesfor some organophosphate carbamates or organochlo-rine insecticides,and have been used extensivelyfor morethantwo decades[1].Pyrethroids are preferred over otherinsecticides because of their easy degradation into non-toxic or less toxic metabolites under natural conditions.Consequently,there has recently beena dramatic increaseinthe use of pyrethroid pesticides to control insect pests.However,synthetic pyrethroids were also reported …     

Beta-cypermethrin impairs reproductive function in male mice by inducing oxidative stress

Cypermethrin (CYP), an insecticide, has deleterious effects on male reproductive function. The objective was to identify whether the effects of beta-CYP on male reproductive organs were associated with oxidative stress. Three doses of beta-CYP (1, 10, and 20 mg/kg) were administered to male mice for 35 d, with or without vitamin E (20 mg/kg). The moderate (10 mg/kg) and high (20 mg/kg) doses of beta-CYP not only decreased body weight and the weight of the testes, epididymides, seminal vesicles, and prostate (P < 0.05) but also reduced serum testosterone concentration and the expression of steroidogenic acute regulatory protein (P < 0.05), in addition to damaging the seminiferous tubules and sperm development. Furthermore, moderate and high doses of beta-CYP administration decreased sperm number, sperm motility, and intact acrosome rate (P < 0.05). Based on ultrastructural analyses, high doses of beta-CYP produced swelling and degeneration of mitochondria and the smooth endoplasmic reticulum of Leydig cells and caused the formation of concentric circles. These toxic effects of beta-CYP may be mediated by increasing oxidative stress, as the moderate and high doses of this compound increased malondialdehyde and nitric oxide in testes (P < 0.05); reduced the activity of catalase, glutathione peroxidase (GSH-Px), and superoxide dismutase (P < 0.05); and activated ERK1/2 (P < 0.05). Vitamin E reversed the effects of beta-CYP on testosterone production and testis damage (P < 0.05 vs. the high-dose group). Therefore, we inferred that beta-CYP damaged the structure of testes and decreased sperm output by inducing oxidative stress.     

Isomerization and biodegradation of beta-cypermethrin by Pseudomonas aeruginosa CH7 with biosurfactant production

Pseudomonas aeruginosa CH7, isolated from activated sludge, was able not only to isomerize and degrade beta-cypermethrin but also to utilize it as the sole source of carbon and energy for growth and produce biosurfactant. The strain effectively degraded beta-cypermethrin with inocula biomass of 0.1-0.2 g L⁻¹ at 25-35 °C, pH 6-9, and a final concentration of beta-cypermethrin 25-900 mg L⁻¹. Via response surface methodology analysis, we found the optimal condition was 29.4 °C, pH 7.0, and inocula biomass of 0.15 g L⁻¹; under these conditions, about 90% of the beta-cypermethrin could be degraded within 12 days. Noticeably, biosurfactant was detected in the MSM culture of strain CH7, suggesting that the biosurfactant (rhamnolipid) could potentially enhance the degradation of beta-cypermethrin by promoting the dissolution, adsorption, and absorption of the hydrophobic compounds. Therefore, CH7 may serve as a promising strain in the bioremediation of wastewater and soil polluted by beta-cypermethrin.     

高效氯氰菊酯降解菌CH7的分离鉴定及降解条件的优化

从农药厂活性污泥中,分离到一株能以高效氯氰菊酯为唯一碳源生长的细菌CH7。经生理生化试验和16S rD-NA分析,将菌株CH7鉴定为铜绿假单胞菌(Pseudomonas aeruginosa)。采用Box-behnken设计试验、响应面法(response surfacemethodology)优化菌株CH7的降解条件。在最优条件下(29.4°C,pH7.0,接种量0.15g/L),菌株CH7在12d内对100mg/L高效氯氰菊酯的降解率为90%。     

Life history and functional capacity of the microbiome are altered in beta-cypermethrin-resistant cockroaches

Cockroaches are widely perceived to evolve resistance to insecticides. Over-expression of a resistance-conferring gene can be costly and may require energy and resource reallocation for metabolic and developmental processes. To evaluate whether changes in the composition of gut microbiota in Blattella germanica affected its resistance evolution to beta-cypermethrin and to determine the role of gut microbiota in host growth and development, we studied the relationship between insecticide resistance and the diversity and genetic content of gut microbiota in cockroaches. Results suggest beta-cypermethrin-resistant cockroaches (R strain) exhibited a delayed development period and reduced adult longevity compared with susceptible cockroaches (S strain). Based on 16S rRNA gene sequencing and community metagenomics, we found that the relative abundance of Lactobacillus and Acetobacteraceae were significantly lower in the R strain compared with the S strain in the foregut and midgut of both strains. Functional annotation of Kyoto Encyclopedia of Genes and Genomes (KEGG) modules of midgut genes in the two strains revealed that 10.6% were involved in metabolism, while the relative abundance in the R strain was 7.4%. Unigenes were also translated into amino acid sequences and assigned to protein families based on hits to the Carbohydrate-Active enzymes (CAZy) database. This process identified the glycoside hydrolases, glycosyl transferases and carbohydrate-binding modules of the S strain as all being significantly higher in diversity than those in the R strain. Overall, we conclude that fitness-related costs increased in the resistant strain of cockroaches compared with the susceptible strain, and the variation in insect gut microbiota, especially those related to growth and development, was an important influencing factor.